Still, I remained where I was for a moment, studying that passage in question. Opposite each window was an arched doorway, the wood fortified by iron strips and solid save for a gap at eye level that would allow someone to peer inside. On closer look, I saw that heavy locks hung from each latch.

At the realization, my heart began pounding as fiercely as if I were balanced on that open stairway again. I took a deep breath, seeking calm. Perhaps those doors merely led to a series of storage rooms secured by a jealous lord against possible theft, I told myself.

Or perhaps one of those doors concealed something else that the Duke of Pontalba did not want discovered… such as the kidnapped man whom he believed to be his ally’s master engineer, Leonardo the Florentine.

Moving as silently as Pio the hound, I eased my way to the first door and peered through the slot. Another archer’s window within allowed sufficient light into the small chamber for me to make out wooden boxes and barrels piled high. Arms, perhaps? Or grain and other supplies stockpiled in case of an attack? No matter; so many varied containers filled the room that no space remained for a prisoner.

With the same soft steps, I made my way to the next chamber and gazed through the slot. Similar to the first room, this one held rows of crates and piles of bulging cloth sacks. The next room contained much the same, as did the two after. Discouraged, I was prepared to give the final room but a cursory glance.

And then I saw that, unlike the rest, this chamber was empty save for a crude bed that had been placed beneath the archer’s window.

Hardly daring to breathe, I squinted against the mixture of sunlight and shadows that filled the small space. Was that a figure wrapped in the tangle of blankets that covered this cot? I waited a seeming eternity for some sign of movement; then, deciding I must risk a sound lest by waiting I be discovered, I softly called, “Father?”

The blankets stirred, and it was all I could do not to dance in place as I waited in anticipation for a glimpse of my sire’s face. “Father,” I whispered again, impatience overriding prudence. “Father, is that you?”

The blanketed figure rolled from the cot and lurched to a standing position, wavering there a moment before staggering toward me. My moment of relief promptly transformed into a jolt of alarm. Was he ill… or perhaps injured? For any number of hardships might have befallen him in the short time that he’d been in the soldiers’ custody.

As the figure drew closer, I frowned. My father was taller and broader than the swathed person standing beyond the door. Did the Duke of Pontalba perhaps have yet another prisoner under his control? But before I could question this unknown person further, small hands reached up to tug aside the blanket, revealing the face beneath.

I blinked. This certainly was not my father; moreover, this was no man locked within the chamber. Rather, the pale, pinched features and dull brown eyes belonged to a young woman!

“Who are you?” she asked, her voice so thin that I had to strain to hear. “Has the duke repented of his cruelty so that I might be released?”

The blanket had slipped to her shoulders, and I glimpsed a flash of fine silk gown in the deepest of blues. Her outer sleeves were fashionably slit so that her white chemise should have puffed with artful flair between those ribbons of azure fabric. But even in the dim light, I could see that the chemise was gray with dirt and the buoyant puffs flaccid. Her black hair-which must have once been braided with ribbons and twisted into a sleek, elaborate crown-hung untidily down her back.

She was no servant girl, I realized in surprise; moreover, she looked vaguely familiar. With a gasp, I cried, “Are you the Duke of Milan’s cousin, the one sent to Pontalba as a bride?”

She stared uncomprehendingly for a moment before managing a small nod. “I am Marianna, Duchess of Pontalba… much to my eternal grief.”

A tear trickled down one slack cheek, leaving behind a shiny trail, but otherwise she displayed no emotion. For myself, I could do nothing but gape in disbelief.

Though I had never spoken to her, I had encountered this one of Ludovico Sforza’s many young relatives while in my guise as the Contessa Caterina’s maidservant. A cousin to Caterina, as well, the plump Marianna had appeared a flighty girl prone to petulance; still, I had heard that she treated her servants with kindness. Following Caterina’s tragic death, Il Moro had chosen her as a substitute wife to seal his alliance with his new ally, Nicodemo lo Bianco, the Duke of Pontalba. Whether or not Marianna had welcomed that honor, I did not know.

But seeing the girl’s treatment at the duke’s hands, I was abruptly grateful that the delicate and lovely Caterina had not lived to be the bride of that brutal man.

Though knowing the futility of the gesture, I still gave the lock on her door several frantic tugs. The heavy metal mechanism did not budge. Had Leonardo been there, he might have cleverly used a bit of wire to serve as a substitute key. Lacking both the Master’s skill and a piece of wire, I could only rattle the lock in frustration.

“Your Eminence,” I started to address her, to have her cut me short with a wave of one pale hand.

“Pray, do not address me as such, for I would take nothing of his, especially not his titles. I am Marianna.”

“Very well, M-Marianna,” I began again, stumbling a little at the informality of that address. “The lock holds tightly, I fear. I will have to find a key.”

“The guards have the keys. Have you come to free me?” she asked, though with no note of hope in her voice. “Who are you?”

“My name is Delfina,” I replied, deliberately using my true name as I knew she could see nothing of me but my face. In her distraught state, chances were she would be more likely to trust another female than she would a boy.

“I’m a friend to the great master Leonardo at the court of the Duke of Milan,” I went on. “Once, I was a servant to the Contessa Caterina. I am searching for my father, whom I fear is imprisoned by the duke, as well.”

“Milan?”

That single word seemed to penetrate her hazy mind, and she stared at me, eyes widening. “Please, you must take word of my plight to my cousin Ludovico, so that he can rescue me!”

“Do not despair, Marianna,” I replied, careful to keep my tone optimistic despite the anger that filled my breast at the thought of what she had suffered. “I vow upon the saints that Il Moro shall know what has happened. Take comfort, for you soon shall be released.”

I prayed I was not giving her false hope. The matter of the flying machine’s theft aside, surely Il Moro would not let his cousin be imprisoned in such a fashion! As soon as we returned to Milan, I would make certain that the Master knew of Marianna’s cruel fate, so that he could advise his patron. And if Ludovico did not act, I had little doubt that Leonardo would find some way to gain her freedom.

“But what did you do? Why did the duke imprison you?” I wanted to know.

The girl blinked, and another tear slid unheeded down her cheek. “I did nothing save try to flee his cruelty.”

I thought for a moment that she would say nothing more, and I wondered at the wisdom of pressing her. But after a few moments, she appeared to rally her wits about her. Her voice stronger, she went on. “I did my duty as my cousin Ludovico commanded. I tried to forget that the duke-my husband-was not young and handsome. But it did not matter. He cared naught for me from the start.

“Indeed, he wished to have me in his bed only so that he could get me with child. I could have borne that, had he left me in peace the rest of the time. But I had barely unpacked my things when he took from me my pens and my books. By that time, he had already dismissed my servants that had come with me from Milan, so that I was all alone.”